Mold for foam molding and foam molding method

Abstract

A mold 20 B for foam molding which allows efficient production of the foam molded product with accurately finished outer surface, and easy release of the molded product from the mold in the foam molding method is formed of an upper mold portion 21 B and a lower mold portion 22 B. The gas feed means 23 formed of the valve box 25 , the valve element 26 and the like is attached to an opening formed in the bottom surface of the lower mold portion 22 B. The recess portions 51 are formed in each part of the opposite side surfaces 50 a and 50 c of the cavity 50 . The protruding portions 52 are formed on the lower surface of the upper mold portion 21 B so as to be fit to the corresponding recess portion 51 . Upon completion of curing, the upper mold portion is separated to open the mold, air is supplied into the valve box 25 such that air is fed to a space between the molded product 31 B and the bottom surface of the lower mold portion 22 B to push up the molded product 31 B so as to be released from the mold. The empty spaces formed by extraction of the protruding portions 52, 52 allow insertion of the tool and finger thereinto to take the molded product 31 B from the mold.

The invention claimed is: 
     
       1. A foam molding method using a mold for foam molding including an upper mold portion having no recess formed on a lower surface of the upper mold portion, and a lower mold portion defining a cavity, wherein a portion of a vertical side wall of the cavity is recessed to form a recess portion formed on an upper surface of the lower mold portion, and a gas feeder in a bottom surface of the cavity of the lower mold portion, wherein a protruding portion which fits into the recess portion extends directly from the lower surface of the upper mold portion, the method comprising:
 supplying a raw material into the cavity of the lower mold portion; 
 inserting the protruding portion into the recess portion after the raw material is supplied into the cavity; 
 producing foam after clamping the upper mold portion of the mold to the lower mold portion of the mold; 
 separating the upper mold portion from the lower mold portion to open the mold; 
 after separating the upper mold portion to open the mold, feeding gas to a space between a molded product and a bottom surface of the lower mold portion from the gas feeder to release the molded product from the lower mold portion, 
 wherein the separating the upper mold portion from the lower mold portion extracts the protruding portion from the recess portion thereby exposing an empty space; and 
 inserting a finger or a tool into the empty space to remove the molded product from the mold. 
 
     
     
       2. The foam molding method according to  claim 1 , wherein the molded product is formed of a rigid urethane foam. 
     
     
       3. The foam molding method according to  claim 1 , wherein the inserting the protruding portion into the recess portion comprises tightly fitting the protruding portion into the recess portion with no clearance therebetween. 
     
     
       4. The foam molding method according to  claim 1 , wherein the inserting the protruding portion into the recess portion displaces the raw material from the recess portion.